As we get closer to planting, many farmers develop, or consider developing, variable seeding rate prescriptions for their fields. Experience levels vary and, as might be expected, accuracy in prescribing the correct seeding rate in a given field location for any given year varies as well. I thought this would be a good time to share some of my experience as well as my findings from a variable rate corn seeding project I conducted this past growing season.
First, it is important to understand that varying seeding rate is not always the right thing to do. It doesn’t always provide a return on investment, largely because of the year-to-year variability in performance of any given hybrid in any given soil environment. In other words, the weather in a given year, its impact on water movement, transport in a field and on plant available water capacity dictates the economically accurate seeding rate on a given soil/landscape position for that year.
In a study conducted by University of Illinois, the same variety was grown on the same part of a field for three years in a row. The optimum harvest population ranged from 25,000 plants/A. to 35,000 plants/A. depending on if the weather was conducive to a 140 Bu./A. year or a 230 Bu./A. year. So, if you can tell me what the weather is going to do, I can tell you what rate to put where!